21 research outputs found
Small Mammal Community Ecology and Ectoparasite Dynamics in a Tamaulipan Thornscrub Habitat
Small mammals play many roles in ecosystems and are known as great indicators of overall ecosystem function and health, but they are also highly competent hosts for ticks and tick-borne disease. In this study, I gathered data on small mammal community ecology and species diversity, abundance, and overall ectoparasite (i.e., ticks) dynamics in a south Texas Tamaulipan thornscrub habitat. I also assessed differences in these parameters in edge versus interior habitats across a gradient of habitat fragmentation and species assemblage. Lastly, I assessed which host and environmental factors can be utilized for predicting parasitization of small mammals in this habitat. Results of this study included a total of nine small mammal species collected with Sigmodon hispidus (n=581) and Peromyscus leucopus (n=443) being the most abundant. Sigmodon hispidus contained the highest species richness of ticks and P. leucopus contributed 79% of all ticks collected. A total of seven tick species were collected, with Dermacentor variabilis (n=982; 66%) being most abundant. There was no statistical difference found between edge and interior habitats for diversity of small mammals (F=1.56; P=0.24), diversity of ticks (F=0.14; P=0.72), or tick loads of any species including Chaetodipus hispidus (F=1.82; P=0.18), Neotoma micropus (F=1.67; P=0.237), Onychomys leucogaster (F=0.99; P=0.322), Peromyscus leucopus (F=1.65; P=0.199), Perognathus merriami (F=1.22; P=0.271),
Reithrodontomys fulvescens (F=1; P=0.334) and Sigmodon hispidus (F=0.72; P=0.397). However, distance from trail and diversity of vegetation were important factors in predicting tick parasitization of small mammals. Other factors which resulted in increased tick loads on small mammals were sex (F=9.09; P=0.003) and the interaction between sex and reproductive status (F=4.5; P=0.03) for Sigmodon hispidus, as well as sex (F=4.09; P=0.04) and reproductive status (F= 5.74; P=0.02) for Peromyscus leucopus. The AICc modeling results for all small mammals indicated that the model that included season, year, vegetative diversity, litter depth, canopy cover, small mammal species, sex, and reproductive status was the most informative model in predicting parasitization of small mammals (AICc= 950.45; wi = 0.14). These parameters along with others presented in each of the models can be utilized in lowering disease risk in arid habitats such as South Texas
Hands-on Science. Advancing Science. Improving Education
The book herein aims to contribute to the advancement of Science to the
improvement of Science Education and to an effective implementation of a
sound widespread scientific literacy at all levels of society. Its chapters reunite
a variety of diverse and valuable works presented in this line of thought at the
15th International Conference on Hands-on Science “Advancing Science.
Improving Education
Impact of climate change on youth in small island communities: The case of St. Vincent and the Grenadines
Building the resilience of youth to adapt to the impact of climate change is a significant development challenge faced by policymakers in Small Island Developing States (SIDS). Climate Change is already impacting negatively on youth and their communities, their enterprises and their overall wellbeing, especially in locations exposed to seasonally intense climatic events. Little progress has been made in the last two decades on how to systemically reduce vulnerability in the broader context of human and environmental systems. Minimal understanding is known on the youth perspective of climate change. This knowledge gap denies policymakers and practitioners effective climate change education and adaptation strategy implementations in preparation for youth resilience against the impacts of future climate changes. The research explores the knowledge deficit between that which is known and that which is necessary for young people to enhance local resilience to climate change. Primary data was collected through interviews with sixteen policymakers, focus group discussions with eleven youth-related organisations, participatory mapping and case studies. Theories around youth development, education and training for climate adaptation in SIDS were reviewed and implemented in the development of a framework assessing the vulnerability of youths living in small island communities. The research explores the strategic effectiveness of actions within the context of top-down vs bottom-up approaches. The framework provides policymakers with a toolkit to enhance youth resilience capacity in SIDS to create sustainable livelihoods in SID communities. The study confirms notions that youth have been neglected in climate change schemes, having inadequate knowledge and skills to adapt to climate changes affecting them. Findings support the added value of the bottom-up approach compared to the use of the top-down method within the framework to improve youth practicality and awareness. Added value can be gained when using a hybrid top-down and bottom-up approach (refer to the definition of
terms on pg. xi-xiii). Findings also highlight key change enablers such as technological innovation, financial and technical resource support, key officials’ engagement, conducive policy/organisational environment and regional collaborations for youth empowerment in adapting to climate change in SIDS. The outcomes of the research discussed with key stakeholders in St. Vincent and the Grenadines found the framework applicable for Climate Change Adaptation (CCA) on the island. Therefore, based on the similarities of SIDS, this may encourage the application of the framework in other SIDS contexts and environments. Overall, the findings fill a gap in the literature on youth and CCA in SIDS. The framework would encourage further research potential in impact assessment and adaptation areas
Interactive visualization of event logs for cybersecurity
Hidden cyber threats revealed with new visualization software Eventpa
Essays in Corporate Finance
This dissertation consists of three chapters in corporate finance and private equity. Chapter 1, “Incentives of Private Equity General Partners from Future Fundraising”, co-authored with Ji-Woong Chung, Berk Sensoy and Michael Weisbach, studies the incentives of private equity general partners (GPs). Lifetime incomes of GPs are affected by their current funds’ performance not only directly, through carried interest profit-sharing provisions, but also indirectly by the effect of the current fund’s performance on GP’s abilities to raise capital for future funds. In the context of a rational learning model, which we show better matches the empirical relations between future fundraising and current performance than behavioral alternatives, we estimate that indirect pay for performance from future fundraising is of the same order of magnitude as direct pay for performance from carried interest. Consistent with the learning framework, indirect pay for performance is stronger when managerial abilities are more scalable and weaker when current performance is less informative about ability. Specifically, it is stronger for buyout funds than for venture capital funds, and declines in the sequence of a partnership’s funds. Total pay for performance in private equity is both considerably larger and much more heterogeneous than implied by the carried interest alone. Our framework can be adapted to estimate indirect pay for performance in other asset management settings.
Uncertainty is ubiquitous in financial markets, and market participants form expectations and learn about parameters, which may be the ability of general partners or the quality of a firm’s governance structure. Assessing the quality of a firm\u27s governance is valuable, which might explain the recent growth of the governance industry. Yet, governance indices have been criticized by researchers and practitioners alike, mainly on the grounds of overlooking firms\u27 heterogeneity and their specific governance needs. Chapter 2, “D&O Insurance and IPO Performance: what can we learn from insurers?”, co-authored with Martin Boyer, provides new insights into the ability of directors’ and officers’ (D&O) insurers to price risk, and in particular risk related to governance characteristics. Therefore, learning by investors about governance quality could be facilitated by providing investors with a market-based assessment of governance as reflected in the D&O insurance premium. We investigate whether a firm’s D&O liability insurance contract at the time of the IPO is related to insured firms’ first year post-IPO performance. We find that insurers charge a higher premium per dollar of coverage to protect the directors and officers of firms that will subsequently have poor first year post-IPO stock performance. A higher price of coverage is also associated with a higher post-IPO volatility and lower Sharpe ratio. Our results are robust to various econometric specifications and suggest that even when the high level of information asymmetry inherent to the IPO context prevails, insurers have information about the firms’ prospects that should be valuable to outside investors.
In Chapter 3, “A Learning-Based Approach to Evaluating Boards of Directors”, I develop a general framework based on a theoretical model of learning to assess how investors react to the appointment of new directors. Using predictions from a learning model, this chapter exploits the cross-sectional variation in the learning-induced decline in stock return volatility over director tenure to infer the marginal value of different kinds of directors. This new framework confirms prior empirical findings and documents new results. For example, directors joining better compensated boards have higher marginal value while the marginal value of a director joining an entrenched board is muted. Furthermore, the estimates imply that governance related uncertainty associated with the arrival of a new director accounts for 7% of return volatility, shedding light on the extent to which governance matters
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Image processing methods to segment speech spectrograms for word level recognition
The ultimate goal of automatic speech recognition (ASR) research is to allow a computer to recognize speech in real-time, with full accuracy, independent of vocabulary size, noise, speaker characteristics or accent. Today, systems are trained to learn an individual speaker's voice and larger vocabularies statistically, but accuracy is not ideal. A small gap between actual speech and acoustic speech representation in the statistical mapping causes a failure to produce a match of the acoustic speech signals by Hidden Markov Model (HMM) methods and consequently leads to classification errors. Certainly, these errors in the low level recognition stage of ASR produce unavoidable errors at the higher levels. Therefore, it seems that ASR additional research ideas to be incorporated within current speech recognition systems. This study seeks new perspective on speech recognition. It incorporates a new approach for speech recognition, supporting it with wider previous research, validating it with a lexicon of 533 words and integrating it with a current speech recognition method to overcome the existing limitations. The study focusses on applying image processing to speech spectrogram images (SSI). We, thus develop a new writing system, which we call the Speech-Image Recogniser Code (SIR-CODE). The SIR-CODE refers to the transposition of the speech signal to an artificial domain (the SSI) that allows the classification of the speech signal into segments. The SIR-CODE allows the matching of all speech features (formants, power spectrum, duration, cues of articulation places, etc.) in one process. This was made possible by adding a Realization Layer (RL) on top of the traditional speech recognition layer (based on HMM) to check all sequential phones of a word in single step matching process. The study shows that the method gives better recognition results than HMMs alone, leading to accurate and reliable ASR in noisy environments. Therefore, the addition of the RL for SSI matching is a highly promising solution to compensate for the failure of HMMs in low level recognition. In addition, the same concept of employing SSIs can be used for whole sentences to reduce classification errors in HMM based high level recognition. The SIR-CODE bridges the gap between theory and practice of phoneme recognition by matching the SSI patterns at the word level. Thus, it can be adapted for dynamic time warping on the SIR-CODE segments, which can help to achieve ASR, based on SSI matching alone
Connectivity: An Ecological Paradigm for the Study of Bronze Age
“Connectivity: an ecological paradigm for the study of Bronze Age” addresses the relationship between historic and prehistoric people, and the landscapes they inhabited, moved about, and continue to inhabit. It suggests alternative methodological approaches that have broader ramifications for the discipline of (Bronze Age) archaeology. By engaging the code and innovations stemming from ecology and digital technology, the research questions concern the interface – referred to as connectivity – between the archaeological sites, resources, networks of communication, and the conditions of archaeological knowledge acquisition. Drawing on published and new data, the aim of the project is to put forward a strategy for a geographically and linguistically inclusive research of the Bronze Age Collapse, analyzing landscape connectivity that does not promote culture as a common denominator of archaeological data sets. Topics that are explored: archaeometallurgy, environmental pressures, mobility, pottery analysis - can be distilled to the issue of scalability of archaeological scholarship. The narrower case study focuses on the southeastern Europe 1650-1100 BCE
THE ROLE OF JAVANESE CULTURE IN CHARACTER BUILDING AT ELEMENTARY SCHOOL
Nowadays, character education becomes a major concern in Indonesia. Character development has been done
by various strategy, but the results is yet to be seen. Character development should beginin elementary school
in order that the children's charactercould formed early so that it could be developed until they are mature.
One of the efforts of character building is integrating the local wisdom in learning. One of them is the
Javanese culture. Javanese culture has a variety of rules called the "unggah-ungguh" that always give good
models to the public community, especially to the Javanese. Along with the times, the Javanese culture that
upholds ethics began to degraded and replaced by foreign cultures that came later. The parents’ roles in
instilling the Javanese culture to their children also decreased gradually. This paper will examine the Javanese
culture’s roles toward the character building in elementary schools’ students. Descriptive method supported by
a depth review of the literature and the previous studies is used in this paper as a method. Based on the results
of these reviews, we obtain some information about the types and mechanisms of Javanese culture in character
building of students, especially elementary school students